The present invention relates generally to a surgical assembly, and more particularly to an apparatus and method for mixing bone cement.
It is necessary in many orthopedic surgical procedures to employ a cement or grouting type agent, such as for attaching artificial joint implants, repairing or forming joints in bones, or other forms of orthopedic work. The type of cement generally used for these purposes is a self-curing resin formed from the blending of a wide variety of liquid monomers or comonomers with powdered polymers or copolymers to form a viscous admixture to be used as the grouting agent.
The admixture of the powder and liquid components develops a quick setting material. As such, preparation of the cement usually occurs directly within the operating area just prior to use. In particular, a bone cement mixing apparatus is generally utilized to mix the powder and liquid components in the operating area. The resultant admixture is then removed from the mixing apparatus and placed in a cement delivery apparatus for subsequent use by the surgeon. Specifically, the bone cement must generally first be scooped or otherwise removed from the mixing apparatus and thereafter placed in a syringe-type delivery apparatus for use by the surgeon.
The aforedescribed system for mixing and delivering bone cement has a number of drawbacks associated therewith. For example, monomer vapors are generated during the depositing of the monomer into the mixing apparatus and during the subsequent mixing of the monomer with the powder component of the bone cement. Such monomer vapors may be noxious and/or toxic. Because the bone cement is generally mixed in the operating room environment, it is important to prevent any monomer or its vapors from escaping the mixing apparatus. However, heretofore designed mixing apparatus have not included mechanisms for controlling the escape of such vapors.
Moreover, heretofore designed mixing apparatus have been plagued with problems relating to the incomplete mixing of the liquid component and the powder component. Specifically, the powder component and liquid component are often inadequately mixed during operation of heretofore designed systems. Such a problem is further compounded by the fact that heretofore designed mixing vessels are not transparent thereby preventing the contents of the vessel (i.e. the bone cement) from being viewed by the operator of the mixing apparatus.
In addition, the aforedescribed system also suffers from operational inefficiencies relating to the need to transfer the mixed bone cement from the mixing apparatus to the delivery apparatus. Specifically, the need to remove the mixed bone cement from one device (i.e. the mixing apparatus) and place it in a second device (i.e. the delivery device) creates an extra step in the process thereby increasing the time necessary to deliver the mixed bone cement. Moreover, a quantity of the bone cement is lost in the process since it is highly unlikely that all of the mixed cement is actually removed from the mixing apparatus and placed in the delivery apparatus.
What is needed therefore is an apparatus and method for mixing a bone cement which overcomes one or more of the above-mentioned drawbacks. What is particularly needed is an apparatus and method for mixing bone cement which reduces, if not eliminates, exposure to vapors from the liquid bone cement component within the operating area. What is further needed is an apparatus and method for mixing bone cement which may also be utilized to delivery the mixed bone cement. What is moreover needed is an apparatus and method for mixing bone cement which reduces, or even eliminates, the occasions in which a portion of the powder cement component is not thoroughly mixed with the liquid cement component.
In accordance with the concepts of the present invention, there is provided a bone cement mixing device having a canister which is modular in design and constructed from a transparent material. The mixing device further has a mixing head assembly having a crank which is operatively coupled to a mixing blade via a gear train. The gear train is configured to drive the mixing blade in a reciprocating manner including the varying of the angular velocity, direction of travel, and angular distance of travel of the blade while the crank is rotated at a constant velocity and direction. The mixing blade has a fluid passage defined therein which allows the liquid cement component to be delivered at various locations within the mixing chamber of the canister.
Pursuant to another embodiment of the present invention, there is provided a bone cement mixing apparatus which includes a handle. The bone cement mixing apparatus further includes an input gear which is caused to rotate about a central axis in response to rotation of the handle, wherein (i) the input gear includes a first input gear teeth set and a second input gear teeth set, (ii) the first input gear teeth set is spaced a first radial distance from the central axis, (iii) the second input gear teeth set is spaced a second radial distance from the central axis, (iv) the second radial distance is greater than the first radial distance, (v) the first input gear teeth set extends outwardly away from the central axis, and (vi) the second input gear teeth set extends inwardly toward the central axis. The bone cement mixing apparatus additionally includes an intermediate gear, wherein the input gear is configured so that during rotation thereof (i) the first input gear teeth set meshingly engages the intermediate gear during a first period of time, and (ii) the second input gear teeth set meshingly engages the intermediate gear during a second period of time which is different from the first period of time. The bone cement mixing apparatus also includes an output gear which is caused to rotate in response to rotation of the intermediate gear. Further, the bone cement mixing apparatus includes a mixing blade which is caused to rotate in response to rotation of the output gear.
Yet according to another embodiment of the present invention, there is provided a bone cement mixing apparatus which includes a handle and an input gear which is caused to rotate in response to rotation of the handle. The bone cement mixing apparatus also includes an intermediate gear which is caused to rotate in response to rotation of the input gear, and an output gear which is caused to rotate in response to rotation of the intermediate gear. Further, the bone cement mixing apparatus includes a mixing blade which is caused to rotate in response to rotation of the output gear. In response to the input gear being rotated one revolution, the intermediate gear is driven (i) a first rotational distance in a counterclockwise direction of rotation, and (ii) a second rotational distance in a clockwise direction of rotation. Additionally, the first rotational distance is less than the second rotational distance.
Yet according to another embodiment of the present invention, there is provided a bone cement mixing apparatus (i) a handle, (ii) an input gear which is caused to rotate in response to rotation of the handle, (iii) an intermediate gear which is caused to rotate in response to rotation of the input gear, (iv) an output gear which is caused to rotate in response to rotation of the intermediate gear; and (v) a mixing blade which is caused to rotate in response to rotation of the output gear. The intermediate gear is driven to rotate at a first output angular velocity during a first period of time in response to the input gear being rotated at an input angular velocity. Also, the intermediate gear is driven to rotate at a second output angular velocity during a second period of time in response to the input gear being rotated at the input angular velocity. Moreover, the first angular velocity is less than the second angular velocity, and the first period of time is different from the second period of time.
In accordance with still another embodiment of the present invention, there is provided a bone cement mixing apparatus which includes an input gear which is configured to rotate about a central axis, wherein (i) the input gear includes a first input gear teeth set and a second input gear teeth set which are spaced apart from each other, and (ii) the first input gear teeth set extends outwardly away from the central axis, and (iii) the second input gear teeth set extends inwardly toward the central axis. The bone cement mixing apparatus further includes an intermediate gear, wherein the input gear is configured so that during rotation thereof (i) the first input gear teeth set meshingly engages the intermediate gear during a first period of time, and (ii) the second input gear teeth set meshingly engages the intermediate gear during a second period of time which is different from the first period of time. Moreover, the bone cement mixing apparatus also includes a mixing blade which is caused to rotate in response to rotation of the intermediate gear.
According to yet still another embodiment of the present invention, there is provided a bone cement mixing apparatus includes an input gear which is configured to rotate about a central axis, wherein (i) the input gear includes a first input gear teeth set and a second input gear teeth set which are spaced apart from each other, and (ii) the first input gear teeth set extends outwardly away from the central axis, and (iii) the second input gear teeth set extends inwardly toward the central axis. The bone cement mixing apparatus further includes a slave gear which is caused to rotate in response to rotation of the input gear. The bone cement mixing apparatus also includes a mixing blade which is caused to rotate in response to rotation of the slave gear.
It is therefore an object of the present invention to provide a new and useful apparatus for mixing bone cement.
It is moreover an object of the present invention to provide an improved apparatus for mixing bone cement.
It is a further object of the present invention to provide a new and useful method for mixing bone cement.
It is also an object of the present invention to provide an improved method for mixing bone cement.
It is yet another object of the present invention to provide an apparatus and method for mixing bone cement which reduces, if not eliminates, exposure to vapors from the liquid bone cement component within the operating area.
It is moreover an object of the present invention to provide an apparatus and method for mixing bone cement which may also be utilized to delivery the mixed bone cement.
It is a further object of the present invention to provide an apparatus and method for mixing bone cement which reduces, or even eliminates, the occasions in which a portion of the powder cement component is not thoroughly mixed with the liquid cement component.
The above and other objects, features, and advantages of the present invention will become apparent from the following description and the attached drawings.